Being able to sense the position and location of one or more elements of a linear motor moving on a platen is important. This invention relates to sensing the location of elements which move on a base in an open loop fashion. Certain linear stepper motors do not have a closed loop operation so there is no feedback to indicate whether the moving element has reached or overshot its destination. This can create significant problems when the moving element is wrongly positioned and work is to be performed on the workpiece associated with the moving element.
There is accordingly a need to have apparatus and a method for minimizing this problem. This invention is directed to solving this difficulty and providing apparatus and a method of sensing and controlling the location of the moving portion of a linear motor over a platen.